Plasma Current (I_p)

The plasma current generates the confining poloidal field and sets many limits. Kronos runs a high I_p = 42.5 MA — its least-forgiving parameter.

Symbol

I_p

Kronos value

42.5 MA (Mode C)

Sets

Poloidal field, q95, Greenwald density, disruption energy

Robustness

The least forgiving parameter (S79)

The plasma current (I_p) is the electric current flowing toroidally through the plasma itself. It generates the poloidal magnetic field that, combined with the external toroidal field, produces the twisted field lines that confine the plasma. Almost every other limit — the safety factor, the Greenwald density, the disruption energy — scales with it.

Kronos MetroVolt runs a high plasma current of I_p = 42.5 MA. The robustness study (S79) found it to be the design's least forgiving parameter: a 5% field reduction can be recovered with a density trim, but a 10% shortfall in plasma current cannot — which is why the current is held with margin rather than run to the edge.